Lionel Tarassenko, CBE, FREng, FMedSci (born 17 April 1957) is a British engineer and academic, who is a leading expert in the application of signal processing and machine learning to healthcare. He was previously Head of Department of Engineering Science (Dean of Engineering) at the University of Oxford, succeeded by Ronald A. Roy. Towards the end of his time as Dean, the Department rose to number 1 in the Times Higher Education World University Rankings.